Lab 12 Human Genetics
.docx
keyboard_arrow_up
School
South Texas College *
*We aren’t endorsed by this school
Course
1408
Subject
Biology
Date
Dec 6, 2023
Type
docx
Pages
29
Uploaded by UltraProton9047
Note: All your answers to questions must be in Red or other color (not
including blue) for easier grading. Points will be deducted if you do not
distinguish your answers.
Lab 12. Patterns of Inheritance
Objectives:
Determine
the genotype by observation of individuals with given
traits and their relatives.
Determine
inheritance involving autosomal dominant, autosomal
recessive and x-linked recessive alleles.
Determine
inheritance involving multiple allele inheritance and use
blood type to help determine paternity.
Describe
a normal human karyotype and discuss the various
abnormalities that can be detected using this technique
Using a karyotype
analyze
a patient’s chromosomes to determine if
inheritance is normal or a chromosomal anomaly is present.
Analyze
a pedigree to determine the pattern of inheritance for an
allele – autosomal dominant, autosomal recessive or x-linked recessive.
Create
a pedigree to determine the probability of inheritance of a
particular phenotype when given generational information only.
Vocabulary:
Genotype
Phenotype
Autosomal dominant
Autosomal recessive
Heterozygous
Homozygous
Probability
X-linked recessive
X-linked dominant
Multiple alleles
Codominance
Karyotype
Pedigree
Introduction:
Just like in pea plants, Mendel’s laws of inheritance also apply to
humans. Humans inherit 46 chromosomes that occur in 23 pairs, 22 pairs of
autosomes
and one pair of
sex chromosomes
(either XX or XY). This
means that all autosomal genes exist in two forms, called alleles. These
alleles may be genetically identical, called
homozygous
(AA or aa) or they
may be genetically different (Aa or aA). The fact that one allele may be
dominant over the other determines what phenotype is exhibited.
Dominant
alleles are represented by capital letters (A) and
recessive
are represented
by lower case (a). Thus, you can have
homozygous dominant
(AA) or
homozygous recessive
(aa) and of course
heterozygous
(Aa).
When a gene follows Mendel’s laws of inheritance (MOST genes do
not), it is easy to predict the ratios of potential offspring using Punnett
squares, or for example to determine the genotypes of parents from the
genotype or phenotype of the offspring. In this section of the lab, we will
practice determining the genotype given information about the gene and
inheritance of it.
Part 1: Determining Genotype
Table 1
shows several autosomal human traits and indicates which is
dominant and which is recessive. Fill out Table 1 and answer the following questions.
(If you are not sure what the trait looks like, refer to
Figure 1-5
, or you can do a
quick internet search for an image of that trait.)
Figure 1:
Left – Widow's peak (dominant) versus Right– straight hairline (recessive).
Figure 2:
Left – No Hitchhiker’s thumb (dominant) versus Right– Hitchhiker’s thumb (recessive).
Figure 3:
Right
– attached earlobes (recessive) versus Left– unattached earlobes (dominant).
Figure 4:
Left– freckles (dominant) versus Right– no freckles (recessive).
Figure 5:
Left– dimples(dominant) versus Right– no dimples (recessive).
Trait
(Capital letter – dominant allele)
(Lowercase letter– recessive allele)
Possible
Genotype
s
Your
Phenoty
pe
Your
Genotyp
e
Widow’s peak – W
Straight
hairline – w
WW, Ww,
ww
Widow’s
peak
Ww
Earlobes unattached – U
Earlobes attached – u
UU, Uu, uu
Earlobes
unattach
ed
Uu
Skin pigmentation:
Freckles – F
No freckles – f
FF. Ff,
ff
No
freckles
ff
Hair on back of hand – H
NO hair on back of hand – h
HH, Hh, hh
No hair
on back
of hand
hh
Dimples – D
No Dimples – d
DD, Dd,dd
No
dimples
dd
Polydactyly (more than 5 fingers)
– P
Five fingers – p
PP ,Pp, pp
Five
fingers
pp
Thumb hyperextension –
“hitchhiker’s thumb”
Last segment cannot be bent
backward – T
Last segment can be bent
backward - t
TT, Tt, tt
Last
segment
can’t
bent
backwar
d
Tt
Questions:
1.
What is the homozygous recessive genotype for dimples? What is the
phenotype?
The homozygous recessive is dd. The phenotype is no
dimples.
2.
Does an individual with Pp exhibit the symptoms of polydactyly (more
than 5 fingers)? Why or why not?
Yes, any person with polydactyly has the
genotype of Pp, where P represents the allele that causes polydactyly and
p presents the normal allele of this gene.
3.
What is the genotype for an individual who is heterozygous for
hitchhiker’s thumb? Will they exhibit the phenotype for hitchhiker’s
thumb?
The genotype for someone who is heterozygous for hitchhiker’s thumb is
Tt. They will not exhibit the hitchhiker’s thumb phenotype instead they
will have a straight thumb.
4.
Two people who are heterozygous for earlobes unattached have a child.
List the genotypes possible for their children regarding earlobe
attachment. Show your work.
UU (for earlobes unattached)
Uu (for earlobes unattached)
Uu (for earlobes unattached)
uu (for earlobes attached)
5.
Ryann does not have freckles, but both their parent’s do. Deduce the genotype
of their parents. What is Ryann’s genotype?
The parents genotype are FF and Ff. Ryann’s genotype is ff.
6.
Godric is heterozygous for widow’s peak and has no hair on the back of his hand.
His partner has a straight hairline and is heterozygous for hair on the back of
their hand.
a.
What is Godric’s genotype?
Ww , hh
(heterozygous widow’s peak; no
hair back of hand)
b.
What is his partner’s genotype?
ww , Hh (straight hairline,
heterozygous-hair back of hand)
c.
What possible genotypes will their children have for hair lines?
WW,
Ww, ww
d.
What possible genotypes will their children have for hair on the back of
the hand?
Hh, hh
Part 2: A Taste of Genetics – Life Example with Taste
Every organism on Earth has a different way to perceive the world due
to their individual life experiences as well as their genetic make-up. Humans
are no different; every individual has their own experiences that shapes their
world perception but so too does their DNA. You may be surprised to learn
that 99.9% of the human genome is identical from one individual to the next,
and it is the 0.1% difference that makes each individual unique.
Some of these differences can affect our sensory systems and how we
perceive the natural world. For example, over time we have learned which
things taste good and are good for us while simultaneously learning which
things taste bad or are bad for us. Specifically, bitter compounds are closely
associated to toxic substances in nature. The way we know things taste
bitter, or any other flavor for that matter, is because we have special
chemical receptors in our mouth and nose that bind molecules in our food
and send signals to the brain telling it what the food tastes like.
Figure 6:
A chemical binding a membrane receptor
One type of bitter receptor in our mouth senses the presence of a
chemical called phenylthiocabamide, or PTC. PTC is a non-toxic chemical, but
it very closely resembles toxic compounds often found in food. The unique
thing about PTC is that not everyone can taste it! We first learned this in the
1920s when Arthur L. Fox and C. R. Noller were working with PTC powder and
Noller complained about the extremely bitter taste while Fox tasted nothing
at all. This led to experimentation where scientists ultimately discovered the
ability to taste PTC was hereditary; it was in our DNA!
The ability to taste PTC comes from the gene
TAS2R38
which encodes
one of the chemical receptors in our mouth that binds to PTC. By comparing
PTC tasters to non-tasters, scientists have found three single nucleotide
polymorphisms (SNPs)
that differentiate the taster allele (T) from the non-
taste allele (t). A SNP is a genetic mutation where one nucleotide in DNA is
different from one individual to the next. The word mutation sounds scary,
but a mutation is not always bad; there are nearly 10 million SNPs in humans
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Related Questions
Complete the sentences with the appropriate term.
recessive
retained some
25%
possible
50%
dominant
lost all
not possible
The mutations found in the HD allele result in a
protein that has
normal activity.
The pattern of inheritance of Huntington disease
indicates that the HD disease allele is
to the normal (HD") allele.
If a mother is heterozygous for the normal and disease-
causing HD alleles and a father is homozygous for the
normal allele, it is
all their children will
have Huntington disease.
Offspring of individuals that have only one parent with
the mutant HD alleie have a
chance
of having Huntington disease.
arrow_forward
Please complete answers than rating helpful other wise un helpful please complete
arrow_forward
Identify the term that best matches the definition or description given.
containing two different
alleles for a trait
the allele that masks
expression of another
allele
breeding with a
homozygous recessive
individual to determine
1.
test cross
2.
genotype
genotype
3.
autosomal
a picture showing
inheritance of a trait over
several generations
phenotype
5.
heterozygous
the appearance of a trait
6. dominant
which alleles are present
in an individual for a trait
4.
arrow_forward
Answer all the questions correctly.
arrow_forward
SUBJECT: GENETICS
Topic: Polygenic Inheritance
Question: Discuss possible presentation why a given family with 12 children, has 7 variations/differences in terms of height (contributing alleles like AABBCCDDEEFF, non-contributing alleles, aabbccddeeff)
arrow_forward
Answer
arrow_forward
Directions: Analyze the given situation and answer the questions.
Hemophilia is a disease caused by a gene found on the X
chromosome. Therefore, it is referred to as a sex-linked disease.
The recessive allele causes the disease. A man with hemophilia
(XnY) marries a woman who is homozygous dominant (XHXH).
A. Illustrate using a Punnett square the probability that their children will have
the disease.
B. Will any of their children have the disease?
C. Predict the probabilities of their children having the disease.
arrow_forward
mentum.com/courseware-delivery/ua/49006400/724263801/aHR0cHM6Ly9mMi5hcH.
Savvas EasyBridge
Google Slides
Infinite Campus M Inbox-francis.a@s...
mosomal Inheritance: Tutorial
What offspring will result from the mating of a non-carrier female and a
?
hemophilic male?
Half of the sons are hemophillacs and half are not. All of the daughter
carriers.
None of the sons are hemophiliacs, and all of the daughters are carrie
None of the daughters are hemophiliacs, and all of the sons are carrier
O Half of the daughters are hemophiliacs and half of the daughters are c
None of the sons are hemophiliacs.
arrow_forward
I need help with these questions please
Thank you:)
arrow_forward
Please tell me what is the correct answer.
arrow_forward
Please help with all parts of this question. Ensure to double and triple check your answers bc I have an exam and I will be using this as my study guide so obviously I don't want to study wrong.
arrow_forward
Complete each sentence with the appropriate term or phrase.
dependent on
The maternal effect refers to the fact that
the phenotype of the offspring is
depenedent on the
mother.
75% dextral and
25% sinistral
of the
1:2:1
Maternal effect genes such as those that
control snail shell twisting code for proteins
that are
100% dextral
independent of
With maternal effect genes, the phenotype
of the offspring is
genotype of the father.
the
deposited in the
egg
With maternal effect genes, the ratios of
progeny that have right or left handed twisting
can be predicted since the inheritance of the
alleles follows
genotype
100% sinistral
In a mating of two Dd snails the phenotypic
Mendel's law of
ratio will be
and the
assortment
genotypic ratio will be
2:1
Mendel's law of
segregation
Reset
arrow_forward
PLEASE ANSWER NUMBER 2. THANKYOU!
arrow_forward
URGENT
arrow_forward
Please help with all parts of this question. Ensure to double and triple check your answers bc I have an exam and I will be using this as my study guide so obviously I don't want to study wrong.
arrow_forward
Complete the sentences
You cross two mice with wildtype (long) tails and collect a male offspring with a short tail, who you name Squeak. Tail length is controlled by the gene Lf, which is a paternally imprinted gene in mice. Given that this is an imprinted gene, explain the inheritance and expression of the trait.
1. Squeak’s short tail allele was inherited from the _____ (female, male, or either) parent. That parent did not express the trait because the allele was ____ (unmethylated, methylated) in the parent’s somatic cells and was inherited from that parent’s own ___ (mother, father, either mother or father)2. If Squeak’s offspring inherit the short tail allele from Squeak, will they have short tails? Yes or No?3. If Squeak was a female instead of a male, which answers in this question would change? ____ (some of the answers, all of the answers, or only the one about the offspring)
arrow_forward
Show the complete solution including the Punnett Sq. Lina has dimples, freckles, and a widow’s peak. She is a heterozygous for all of the three traits. David, her husband also has freckles and dimples but has a continuous hairline. As freckle is known to be dominant over none, dimples are dominant over no dimples, and widow’s peak is dominant over continuous hairline, what is the
a) Probability that their child will have three recessiveness: no freckle, no dimples, and has widow’s peak; and
b) Probability that their child will have the same phenotype as Lina (with freckles, dimples, and widow’s peak)?
Legend:
Ff – freckles
Dd – dimples
Ww – widow’s peak
arrow_forward
Please answer attached question.
arrow_forward
Please fill in the following red areas.
arrow_forward
Please help me with this question ASAP at the earliest ???? within an hour will appreciate your help?
arrow_forward
Please answer all of them, they are all connected.
PEDIGREE ANALYSIS and SYMBOLOGY:
Examine the pedigree which has X linked Dominant inheritance of disorder. Use letter X* (asterisk denotes disorder) as genotype of the individuals which can be XX, XY, X*X*, X*X and X*Y.
a. What is the genotype of IV-6?
b. What is the genotype of III-6?
c. What is the genotype of II-3?
d. What is the genotype of III-8?
e. If couple I-1 and I-2 will have a son, what is the probability of having the disorder?
f. If couple III-8 and III-9 will have another child, what is the probability of having the disorder?
g. Theoretically, if individual IV-3 and individual IV-5 will marry and will have a child, what is the probability of having a child without the X-linked disorder?
arrow_forward
SEE MORE QUESTIONS
Recommended textbooks for you
Nutrition Through The Life Cycle
Health & Nutrition
ISBN:9781337919333
Author:Brown, Judith E.
Publisher:Cengage Learning,
Related Questions
- Complete the sentences with the appropriate term. recessive retained some 25% possible 50% dominant lost all not possible The mutations found in the HD allele result in a protein that has normal activity. The pattern of inheritance of Huntington disease indicates that the HD disease allele is to the normal (HD") allele. If a mother is heterozygous for the normal and disease- causing HD alleles and a father is homozygous for the normal allele, it is all their children will have Huntington disease. Offspring of individuals that have only one parent with the mutant HD alleie have a chance of having Huntington disease.arrow_forwardPlease complete answers than rating helpful other wise un helpful please completearrow_forwardIdentify the term that best matches the definition or description given. containing two different alleles for a trait the allele that masks expression of another allele breeding with a homozygous recessive individual to determine 1. test cross 2. genotype genotype 3. autosomal a picture showing inheritance of a trait over several generations phenotype 5. heterozygous the appearance of a trait 6. dominant which alleles are present in an individual for a trait 4.arrow_forward
- Answer all the questions correctly.arrow_forwardSUBJECT: GENETICS Topic: Polygenic Inheritance Question: Discuss possible presentation why a given family with 12 children, has 7 variations/differences in terms of height (contributing alleles like AABBCCDDEEFF, non-contributing alleles, aabbccddeeff)arrow_forwardAnswerarrow_forward
- Directions: Analyze the given situation and answer the questions. Hemophilia is a disease caused by a gene found on the X chromosome. Therefore, it is referred to as a sex-linked disease. The recessive allele causes the disease. A man with hemophilia (XnY) marries a woman who is homozygous dominant (XHXH). A. Illustrate using a Punnett square the probability that their children will have the disease. B. Will any of their children have the disease? C. Predict the probabilities of their children having the disease.arrow_forwardmentum.com/courseware-delivery/ua/49006400/724263801/aHR0cHM6Ly9mMi5hcH. Savvas EasyBridge Google Slides Infinite Campus M Inbox-francis.a@s... mosomal Inheritance: Tutorial What offspring will result from the mating of a non-carrier female and a ? hemophilic male? Half of the sons are hemophillacs and half are not. All of the daughter carriers. None of the sons are hemophiliacs, and all of the daughters are carrie None of the daughters are hemophiliacs, and all of the sons are carrier O Half of the daughters are hemophiliacs and half of the daughters are c None of the sons are hemophiliacs.arrow_forwardI need help with these questions please Thank you:)arrow_forward
- Please tell me what is the correct answer.arrow_forwardPlease help with all parts of this question. Ensure to double and triple check your answers bc I have an exam and I will be using this as my study guide so obviously I don't want to study wrong.arrow_forwardComplete each sentence with the appropriate term or phrase. dependent on The maternal effect refers to the fact that the phenotype of the offspring is depenedent on the mother. 75% dextral and 25% sinistral of the 1:2:1 Maternal effect genes such as those that control snail shell twisting code for proteins that are 100% dextral independent of With maternal effect genes, the phenotype of the offspring is genotype of the father. the deposited in the egg With maternal effect genes, the ratios of progeny that have right or left handed twisting can be predicted since the inheritance of the alleles follows genotype 100% sinistral In a mating of two Dd snails the phenotypic Mendel's law of ratio will be and the assortment genotypic ratio will be 2:1 Mendel's law of segregation Resetarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Nutrition Through The Life CycleHealth & NutritionISBN:9781337919333Author:Brown, Judith E.Publisher:Cengage Learning,
Nutrition Through The Life Cycle
Health & Nutrition
ISBN:9781337919333
Author:Brown, Judith E.
Publisher:Cengage Learning,